Blood after going number 2? O.O?

I'm a little scared right now...so my little sister was sick last night, we ume a stomach bug, she threw up but we took care of it. After that when I was going back to bed, I started to feel sick but I ignored it and then ped out when I woke up I felt fine. So it's been a long time since then, I had some skittles, a mountain dew, and fries from mcdonalds, but not all at the same time. (that's kinda gross) so we had spaghetti for dinner, I started to eat but my tummy started to hurt, so I went to the bathroom and when I wiped there was a tiny tiny tiny line of blood and it kinda scared me, I wiped again and there was a blood clot...but then when I wiped in front thinking it was my period, there wasn't any blood..what could it be? my mom said to check out to see if it happens again and if it does to tell her so we can go to the doctor soon...what could have caused it, because now I'm really scared.